Moldavian dragonhead (Dracocephalum moldavica L.) is an annual herbaceous plant from Lamiaceae family and is known to be native to the temperate climate of Asia. It is recognized that balmscented leaves of dragonhead have some medical influences. Weeds are one of the most important problems in medicinal plant production and may cause a significant loss in both plant yield and their active ingredients. We evaluated the effects of different weed control techniques on the growth, content and composition of essential oils of dragonhead in northwest of Iran. weed control treatments was including No weeding (weedy check); one hand weeding at 20 DAS; two hand weeding at 20 and 40 DAS; weed free (regular hand weeding at 10 days interval until harvest); Treflan herbicide (preemergence control); Gallant Super herbicide (post emergence control) and soil solarization (use of clear polyethylene). Growth parameters, herbage yield and content of essential oil were significantly influenced by different weed control treatments. Result showed that the maximum biological yield and essential oil content were obtained from weed free condition followed by two hand weeding and soil solarization. Essential oil analyses indicated that neral, geraniol, geranial, and geranyl acetate were the most abundant compounds. The lowest amount of neral was recorded in plants grown under chemical weed control. Overall finding of current experiments suggested that eco-friendly approaches, mainly soil solarization and regular manual weeding might be the best option to combat weed problems as well as to obtain satisfactory herbage yield and an acceptable quality of essential oil content in dragonhead. This finding has important implications for developing non-chemical weed control in medicinal plants.
